Suspended ceiling grid system with demountable tiles



Oct. 18, 1966 L. (5. STAHLH UT 3,279,139

SUSPENDED CEILING GRID SYSTEM WITH DEMOUNTABLE TILES Filed Aug. 8, 1965 INVENTOR. 4 60 4". fr/Mu/ur United States Patent Office 3,279,139 Patented Oct. 18, 1966 3,279,139 SUSPENDED CEILING GRID SYSTEM WITH DEMOUNTABLE TILES Leo G. Stahlhut, Kirkwood, Mo., assignor to K-S-Ill Plastics, Inc., Kirkwood, Mo., a corporation of Missouri Filed Aug. 8, 1963, Ser. No. 300,834 3 Claims. (Cl. 52-496) This invention relates to suspended ceilings.

It has become common to form the ceiling of buildings by using a grid of shapes suspended on hangers, such as wires or straps, secured to a permanent overhead supporting structure. Commonly, ceiling tiles are laid on ledges provided by the shapes.

The most common form of grid members has been the so-called T rail. The T is inverted, the head serving to provide a shelf, and the stem, a means of connecting the rail to the wire or strap. The head of the T can also be used as a spline, extending into a kerf in the vertical edge of a ceiling tile. However, in this latter arrangement, it can be seen that the ceiling must be installed serially as a unit, i.e., with the first rail, then the first row of ceiling tile, then the second rail, and so on. It also precludes accessibility to the space between the suspended ceiling and the supporting structure, except in those areas in which special provision is made by not using the T rails as splines.

When ceiling tile is merely laid on the head of the T rail, the tiles tend to breathe. With the advent of extremely lightweight tile, the tiles may actually float from their shelf on the T rails when a pressure differential is created between the room space below the suspended ceiling and the space above it.

One Of the objects of this invention is to provide a suspended ceiling, the grid members of which are unobtrusive in appearance, positively interlocked, and which retain ceiling tiles against unwanted movement, but permit their release when their. release is desired.

Another object of this invention is to provide a suspended ceiling with ceiling tiles peculiary adapted to use with the grid members of this invention.

, Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.

In accordance with this invention, generally stated, a suspended ceiling is provided which exposes only a very small thickness of grid structure between ceiling tiles, but which provides a rigid grid, and a secure mounting for the ceiling tile, which, at the same time, permits the removal of the ceiling tile if its removal becomes desirable, without dismantling the grid.

The grid members of this invention are cruciform in transverse cross-section. They have a heavy, depending stem member, a pair of transversely extending, oppositely disposed, shelf-like arms, integral with the stem, a web integral with the arms and vertically aligned with the stem, and a rib, extending along and integral with the upper edge of the web. The web is thin in transverse section, relative to the thickness of the stem and the rib.

The grid members are made up as main rails and cross rails, identical in section, but differing in the provision for their junctures with one another.

One of the rails has a slot through the stem, from the bottom edge of the stem to the underside of the arms. The other of the rails has an opening which interrupts the web, rib and arms, through a width to receive the full span of the arms of the first rail. This second member is also provided with ear-receiving slots adjacent the opening.

A clip is provided, which has ears extending through the ear-receiving slots in the second member and a bridging piece to embrace the web of the first rail when the two rails are assembled, with the stem of the second in the slot in the stem of the first. When the main and cross rails are thus assembled, a rigid joint is provided, which does not permit objectionable relative movement of the rails in any direction.

Two illustrative embodiments of the grid members of this invention are shown and described. In one, the stem is provided with plane-sided vertical walls. In the other, an arcuate channel is provided in each side wall of the stem, parallel with and adjacent, but above the lower edge of the wall.

Ceiling tiles are provided for use with both embodiments of grid member. Both types of ceiling tile shown and described are unitary pieces of a lightweight, generally cellular, somewhat resilient material. Each has a facing panel of substantial (vertical) thickness, and an inwardly stepped upper wall, also of substantial vertical thickness, which, with the top of the facing panel, defines a horizontal shoulder. In both types of ceiling tile, nosetype stop lugs are provided, which serve to prevent movement of the tile in one direction or the other. In the type of tile to be used with the first embodiment of grid member (with plane-sided vertical stem walls), the nose lugs are provided on the edge faces of the upper wall. On the type of ceiling tile used with the other embodiment of grid member described, the nose lugs are provided on the edge surfaces of the facing panel. In each case, the nose lugs are flared outwardly downwardly, so as to provide a carnming surface when the ceiling is installed from beneath the grid.

In the ceiling tile used with the first embodiment of grid, an arm-receiving groove is provided between the undersurface of the nose lug and the shoulder defined between the facing panel and upper wall. In the ceiling tile used with the second embodiment of grid member, the nose lug is offset upwardly from the lower surface of the facing panel, and is shaped complementarily to the channel in the side wall of the stern.

It can be seen, that, in the two illustrative embodiments shown, the profile of the edge of the facing panel of the second type of tile is identical with the profile of the edge of the upper wall of the first type.

In the drawing, FIGURE 1, is a fragmentary sectional view showing what, in this embodiment, is a main rail in section and a cross rail in side elevation at their juncture, clipped together;

FIGURE 2 is a fragmentary view in side elevation of the side rail of FIGURE 1;

FIGURE 3 is a fragmentary view in perspective, and partly in section, showing a main and cross rail in the process of being joined by a clip of this invention;

FIGURE 4 is a fragmentary view in side elevation of two sections of main rail joined end to end by means of fish plates of this invention;

FIGURE 5 is a sectional view taken along the line 5-5 of FIGURE 4;

FIGURE 6 is a view in perspective of fish plate shown in FIGURE 4, before it is installed;

FIGURE 7 is a sectional view of a grid member along an edge of one embodiment of ceiling tile of this invention; and

FIGURE 8 is a sectional view of another embodiment of grid member along an edge of another embodiment of ceiling tile of this invention.

Referring now to the drawing, and particularly to FIG- URES 1 through 7, for one illustrative embodiment of this invention, reference numeral 1 indicates a main rail grid member, and reference numeral 2, a cross rail grid member. Both grid members 1 and 2 are cruciform in cross section, as shown particularly in FIGURE 3. Each has a heavy separator stem 10, a pair of oppositely projecting shelf-like arms 12, a web 14, integral with the arms 12 and vertically aligned with the stem 10, and a rib 16, extending along and integral with the upper edge of the web 14.

Normally the cross rail 2 is shorter than the main rail 1. For example, for a two foot by four foot module, the main rail may be twelve feet long, the cross rail eight feet long. The main rail will be adapted to receive the cross rails on two foot centers. However, the members can be of various different lengths and notched for different modules.

In the embodiment shown, the main rail is characterized by having spaced notches 30 extending from and through the free (lower) edge of the heavy stem to the underside of the arms 12. Each of the slots 30 is of a width closely but slidably to receive the stem of a cross rail. At the ends of the main rail, the stem 10 of the main rail is offset half the width of a slot 30, so that when two main rail ends are abutted, as illustrated particularly in FIGURE 4, a full slot 30 is defined.

In order to hold successive main rails in abutted relation, fish plates 60 are provided. The main rails have tab-receiving holes 32 through their webs 14, near the free ends of the main rails. Each of the fish plates 60 is L-shaped in end elevation, with a foot 61 and a side 62. The side 62 has a tab slot 63 near one end, and, near its other end, a tab 64, integral at one end with the side 62, and projecting from it. As shown particularly in FIGURES 4 and 5, two fish plates 60 are used, one on each side. The foot 61 of each of the fish plates rests upon the upper face of an arm 12, the tab 64 of each fish plate projects through a hole 32 in a web 14 and through the oppositely disposed, aligned tab-receiving slot 63 in the side 62 of the other fish plate. The projecting tabs 64 are then bent back against the outer surface of the side 62 through which it projects, to form a tight joint.

Referring now to FIGURES 1 through 3, the cross rail 2, in this embodiment, is characterized by spaced openings 40, which interrupt the rib 16, web 14 and arms 12 of the rail. The openings 40 extend through the upper edge of the rail to the upper edge of the stem 10, and the web, contiguous the arms 12, is cut away to provide longitudinally extending, foot-receiving notches 41. Ear receiving holes 43 are provided in the web 14, one at each side of the opening 40. The ends of the cross rail are formed as if a cross rail were cut through the vertical center line within an opening 40.

A clip 50 serves a double purpose. When the main rail and cross rail are to be joined, the clip 50 provides a rigid joint. The clip also serves to join, in end to end relation, two cross rails 2.

The clip 50, in the embodiment shown, includes a pair of skirt members 51 spaced to define between them a slot 58, wide enough closely but slidably to admit the rib 16 of a main rail; cars 52, each integral at its root with the outside edge of a skirt 51, and projecting at right angles to the plane of the skirt; feet 53, each integral at one end with the lower edge of a skirt, and projecting at right angles to the plane of the skirt, and a stepped bridging piece 54, integral with the top edges of the skirts 51 and connecting the skirts 51. The bridging piece 54 has a cap part 55, integral at one edge with the upper edge of the skirts, and projecting at right angles to the plane of the skirts, and, along the other edge of the cap part 55, a flange 56, which is parallel with the plane of the skirts 51. The flange 56 serves to give rigidity to the assembly, serving in effect to extend the rib 16 across the top of the main rail when the clip is installed at a joint with the main rail, or to take the place of the rib 16 when the clip is used merely to splice two cross rails end to end.

Inassembling a cross rail and a main rail, the main rail is brought into the opening 40, with the stem 10 of the cross rail going into the slot 30 of the main rail. The rails are then positioned as shown in FIGURE 3. A clip 50 is then dropped over the rib and stem of the main rail, also as shown in FIGURE 3, and slid into position, with the cars 52 projecting through the ear receiving holes 43, and the feet 53 projecting beneath the web 14 of the cross rail, in and through the foot receiving notches 41. The ears 52 are bent over at right angles, flush with the web 14, and the two rails are held against movement in any direction, within the limits provided by the tolerances of the various parts.

It can be seen that two cross rails can be joined in end to end relation by the same clip. When the clip 50 is in place, the cap 55 and feet 53 clamp spaced horizontal surfaces of the cross rails between them, while the skirts 51 and the cars 52 clamp spaced vertical surfaces between them, thus providing rigidity in all directions.

Two embodiments of grid memebrs of this invention are illustrated in FIGURES 7 and 8. Essentially, they differ only in the provision, in the embodiment of grid members shown in FIGURE 8, of an arcuate channel 80, in each side of the stem, near its lower end. This difference, however, makes a substantial difference in the type of ceiling tile employed.

The embodiment of ceiling tile shown in FIGURE 7 is of a resilient material and has a facing panel 71, an inwardly stepped upper wall 72, a shoulder 73 defined by an upper edge margin of the facing panel and the upper wall, and nose lugs 74 integral with the outside face of the upper wall 72. The nose lugs 74, in this embodiment, are interrupted, spaced along the Wall 72 from one another, and extend around all four sides of the ceiling tile. The lower portion of the edges of the facing panel 71 is flush with the stem 10 of the grid member when the tiles are installed. This embodiment of ceiling tile can be used with either embodiment of grid members.

In the embodiment of ceiling tile shown in FIGURE 8, which is also of resilient material, a facing panel 81 has nose lugs 84 which fit into the channels or the grid members, as shown clearly in FIGURE 8. The ceiling tile of this embodiment also has an inwardly stepped upper wall 82, defining, with the top of the facing panel 81, around its margin, a shoulder 83. It can be seen from FIGURE 8, that the vertical distance between the nose lugs 84 and the shoulder 83 is substantially the same as the vertical distance between the channel 80 and the underside of the arms of the grid member, so that the ceiling tile, when installed, is held against movement up and down. In this embodiment, a portion of the facing panel 81 below the nose lugs 84, fits flush against the side face of the lower portion of the stem, below the channel 80. With this arrangement, the nose lugs 84 may be interrupted, to make installation easier, since the part 85 below the nose lugs will mask the nose lugs.

Both embodiments of ceiling tile are installed from below the grid.

The grid members may be suspended by means of wires taking through holes provided along the web 14, or the clips 50 may be punched through the flange 56 to take a wire or strap.

Thus it can be seen that a ceiling is provided, in which the grid members have greater rigidity than grid members known heretofore, provide a neat joint between adjacent ceiling tile, and permit the installation of ceiling tile from below the grid; in which ceiling tile are provided which are constructed in such a way as to preclude floating or other undesirable movements and are peculiarly adapted to use with the grid members of this invention, and in which clips are provided which perform multiple functions of mounting main and cross rails, holding them n'gid against movement in any direction, and joining successive rails in end to end relation.

The separator stem may be used as support and as a guide for partitions, room dividers and the like. To that end, either a row of tile can be supported on the shelf-defining arms or tile can the provided which either are shallow enough or chamfered at their outer edges to expose a portion of the sides of the stem.

Numerous variations in the construction of various of the elements of the ceiling of this invention within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. For example, if it is desired, clips can be used instead of the nose lugs, to secure the ceiling tile, although this requires more labor and is not as satisfactory as the preferred embodiment described. Even conventional ceiling tile may simply be laid on top of the shelf-defining arms of the grid members, leaving the undersides of the arms exposed as well as the separator stem. Lighting fixtures may, of course, also be so supported. The web of the grid members may be made heavy, although this also is less desirable.

Having thus described the invention, what is claimed and desired to be secured by Leters Patent is:

1. A suspended ceiling wherein a grid of supporting members is suspended from a building structure and ceiling tiles are mounted on the grid, comprising grid members each of which is cruciform in transverse cross section, having a separator stem, a pair of oppositely dis posed shelf-defining arms integral with said stem and extending transversely with respect thereto, and a web integral with said arms and vertically aligned with the stem, and ceiling tiles adapted to be mounted on and demounted from said grid members from beneath said grid, said ceiling tiles comprising a unitary piece of resilient material having a central facing panel of substantial thickness and an inboardly stepped upper wall area defining a shoulder between them, said upper wall area being of substantial thickness, and outboardly projecting stop lugs on the edges surfaces of one of said central facing panel and upper wall area, said stop lugs being sloped inboardly upwardly to provide a camming surface during installation and said stop lugs engaged with a part of the g-rid member to support said ceiling tile, said grid members being rectilinearly disposed and being spaced to receive said tiles between them, and said separator stems having a lower edge exposed between successive of said ceiling tiles.

2. The ceiling of claim 1 wherein the separator stem of the grid members has an arcuate channel along each side parallel with and near its lower edge, and the stop lug on the ceiling takes the form of a nose lug projecting laterally from the outer edge of the facing panel, said nose lug being upwardly offset from the edge: margins of the facing panel but positioned near said edge margin relative to the top surface of the tile, the vertical distance between the nose lug and the upper marginal surface of the facing panel being substantially the same as the vertical distance between the arcuate channel and the arms of the grid member.

3. The ceiling of claim 1 wherein the ceiling tile has its outboardly projecting stop lugs on the outer edge surface of the upper wall, said stop lugs being spaced above the shoulder margin of the facing panel a distance to define an arm-receiving channel therewith.

References Cited by the Examiner UNITED STATES PATENTS 1,242,669 10/1917 Erkens 52-496 X 1,997,092 4/ 1935 Duffy 52-496 X 1,998,423 4/1935 Stubbs 52-494 X 2,005,427 6/1935 Lenke 52-475 2,505,903 5/1950 Madger 52-497 2,710,679 6/1955 Bibb et al. 287-18936 2,926,237 2/1960 Sorenson 52-484 X 3,059,735 10/1962 Sowinski 287-18936 3,087,205 4/ 1963 Mancini 52-475 3,208,561 9/1965 Van Buren 287-18936 FOREIGN PATENTS 248,433 12/ 1963 Australia. 1,253,369 1/1961 France.

651,063 1l/ 1951 Great Britain.

479,211 3/1953 Italy.

355,276 8/ 1961 Switzerland.

FRANK L. ABBOTT, Primary Examiner.

M. O. WARNECKE, Assistant Examiner. 

1. A SUSPENDED CEILING WHEREIN A GRID OF SUPPORTING MEMBERS IS SUSPENDED FROM A BUILDING STRUCTURE AND CEILING TILES ARE MOUNTED ON THE GRID, COMPRISING GRID MEMBERS EACH OF WHICH IS CRUCIFORM IN TRANSVERSE CROSS SECTION, HAVING A SEPARATOR STEM, A PAIR OF OPPOSITELY DISPOSED SELF-DEFINING ARMS INTEGRAL WITH SAID STEM AND EXTENDING TRANSVERSELY WITH RESPECT THERETO, AND A WEB INTEGRAL WITH SAID ARMS AND VERTICALLY ALIGNED WITH THE STEM, AND CEILING TILES ADAPTED TO BE MOUNTED ON AND DEMOUNTED FROM SAID GRID MEMBERS FROM BENEATH SAID GRID, SAID CEILING TILES COMPRISING A UNITARY PIECE OF RESILIENT MATERIAL HAVING A CENTRAL FACING PANEL OF SUBSTANTIAL THICKNESS AND AN INBOARDLY STEPPED UPPER WALL AREA DEFINING A SHOULDER BETWEEN THEM, SAID UPPER WALL AREA BEING OF SUBSTANTIAL THICKNESS, AND OUTWARDLY PROJECTING STOP LUGS ON THE EDGES SURFACES OF ONE OF SAID CENTRAL FACING PANEL AND UPPER WALL AREA, SAID STOP LUGS BEING STOPED INBOARDLY UPWARDLY TO PROVIDE A CAMMING SURFACE DURING INSTALLATION AND SAID STOP LUGS ENGAGED WITH A PART OF THE GRID MEMBER TO SUPPORT SAID CEILING TILE, SAID GRID MEMBER BEING RECTILINEARLY DISPOSED AND BEING SPACED TO RECEIVE SAID TILES BETWEEN THEM, AND SAID SEPARATOR STEMS HAVING A LOWER EDGE EXPOSED BETWEEN SUCCESSIVE OF SAID CEILING TILES. 